Python regex pattern from array of hex chars

[MRAB]

On 2018-04-13 18:28, Joseph L. Casale wrote:
> I have an array of hex chars which designate required characters.
> and one happens to be \x5C or "\". What foo is required to build the
> pattern to exclude all but:
> 
> regex = re.compile('[^{}]+'.format(''.join(c for c in character_class)))
> 
> I would use that in a re.sub to collapse and replace all but those
> in the character_class. Obviously the escape issues break the \x5C
> character.
> 
Use re.escape:

regex = re.compile('[^{}]+'.format(re.escape(''.join(c for c in 
character_class))))